PROJECT SUMMARY The Superfund Research Program at the University of Iowa (isrp) investigates the consequences of atmospheric sources and exposures to semi-volatile, lower-chlorinated polychlorinated biphenyls (PCBs). The biomedical and environmental research projects of the isrp need a variety of study compounds ranging from technical and synthetic PCB mixtures to pure PCB congeners and their metabolites for studies of the volatilization, transport and exposure of these PCB congeners. A major obstacle for these studies is the large number of 209 PCB congeners plus the large number of 837 possible hydroxylated (OH-PCBs), sulfated (PCB sulfates), glucuronidated (PCB glucuronides) and other PCB metabolites. Many of these PCB derivatives are not available from commercial sources or have never been synthesized before. Moreover, obtaining PCB mixtures or individual PCB congeners from commercial sources can be expensive, especially if large quantities are needed for animal studies. Therefore, the MAJOR OBJECTIVE of the Synthesis Core is to provide a large variety of fully characterized and highly pure PCB derivatives to individual research projects and research support cores within the isrp. If time and resources allow, the Synthesis Core will also make study compound available to other researchers, especially researchers from other Superfund Research Programs. At the same time, the Synthesis Core will continue to develop novel synthetic strategies for the synthesis of PCB congeners and PCB metabolites as needed by isrp researchers. The Specific Aims of the Synthesis Core are to 1) maintain and prepare PCB mixtures and pure PCB congeners; 2) prepare hydroxylated PCB derivatives; synthesize PCB sulfate metabolites; and 4) prepare miscellaneous compounds, including OH-PCB glucuronides and diazomethane. Synthesis Core researchers have extensive experience with the preparation, purification and characterization of all compounds requested by isrp research projects. The timely availability of PCB mixtures, individual OH-PCBs, PCB sulfates and other PCB metabolites will greatly enhance and, if the respective PCB metabolites are unavailable, enable the innovative studies proposed by isrp research projects.